domain-checker

# Domain Checker Check domain availability in bulk using RDAP (Registration Data Access Protocol) as the primary signal, with WHOIS and DNS fallbacks. Python stdlib only. ## When to Use - User asks "is `<domain>` available / taken / registered?" - User wants to check many domains at once (a list, a file, names piped in) - User wants to test a brand name across many TLDs (`acme.com`, `acme.net`, `acme.io`, …) - User wants machine-readable output (CSV/JSON) for further processing - User wants only available (or only taken) results filtered Do NOT use for: WHOIS contact lookup (this skill only checks existence), DNS record inspection (use `dig`), trademark/legal availability (this only checks registration status). ## How It Works 1. **RDAP first** — fetches the IANA RDAP bootstrap (`data.iana.org/rdap/dns.json`, cached 24h in `~/.cache/domain-checker/`) to find the authoritative RDAP server for each TLD. `HTTP 404` = available, `HTTP 200` = taken. 2. **WHOIS fallback** — if RDAP is unavailable for a TLD (notably `.io`, some ccTLDs) or returns ambiguous, shells out to the local `whois` CLI and matches well-known "not found"/"registered" patterns. 3. **DNS** — optional, weak signal. Resolves A/AAAA records. Confirms "taken" only — registered-but-unhosted domains will show no DNS, so DNS alone cannot prove "available". After the primary check, three enrichment passes refine accuracy: 4. **Aftermarket detection** — parses the RDAP response we already fetched. Flags `aftermar...